.fixed-fullscreen {
  position: fixed;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}
.fixed-fullscreen-mask {
  position: fixed;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0,0,0,.33);
}
.absolute-fullscreen {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}
.absolute-transform-center {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}
.absolute-margin-center {
  .absolute-fullscreen;
  margin: auto;
}
.fixed-margin-center {
  .fixed-fullscreen;
  margin: auto;
}
.flex-center {
  display: flex;
  justify-content: center;
  align-items: center;
}
